PROJECT SUMMARY/ABSTRACT The need for a diverse environmental health workforce has growing urgency as the population of the planet nears eight billion people and the environmental health impacts of natural disasters and drought become evident on every continent. In addition to understanding how environmental stressors impact human health, scientists of the next generation will need to work across disciplines to develop viable solutions to environmental and social challenges. Yet the disciplines that underpin environmental health sciences?biomedical, clinical and behavioral sciences?lack the diversity that bolsters effective problem solving (Ferrini-Mundy, 2013). More broadly, women, persons with disabilities, and three racial and ethnic groups?people of African American, Hispanic, and/or American Indian and Alaska Native descent?remain underrepresented in science and engineering education programs and employment (NAS, 2011; NSF, 2019). Pursuit of STEM careers requires additional support for all students, especially underrepresented minority and women students who contend with systemic racial and gender bias. For these students, the likelihood of persisting in STEM majors is influenced by opportunities to meaningfully participate in the academic community and develop supportive relationships with faculty and peers (Figueroa et al., 2015; PCAST, 2012; Tsui, 2007). Within this context, the Curriculum in Toxicology & Environmental Medicine (CiTEM) in the UNC- Chapel Hill School of Medicine, together with the UNC Institute for the Environment (UNC-IE) and the Department of Biological and Biomedical Sciences at NC Central University (NCCU), propose an environmental health-focused undergraduate research program to expand and diversify the pool of students entering the environmental health workforce. The 21st Century Environmental Health Scholars program will provide mentored research experiences and professional development for students from diverse backgrounds, with a goal of preparing these students for further studies or research careers in environmental health sciences. We will accomplish this goal through the following aims. Aim 1. Facilitate summer undergraduate research opportunities in environmental health sciences. Aim 2. Facilitate academic-year undergraduate research experiences and broaden professional development to include environmental health sciences careers, science communication, and community engagement. Aim 3. Implement robust mentorship training that incorporates evidence-based practices in mentoring diverse students and cohort building opportunities. Over five years, this program will prepare 25 diverse undergraduates for careers in environmental health sciences, introducing them to cutting-edge research topics and facilitating essential skills development. At the same time, participating mentors will enhance their ability to create and sustain inclusive learning environments. Together, these activities will encourage the participation of individuals from diverse backgrounds to pursue environmental health sciences research and careers.